Then you should know that to move things left, you need to vote more local progressives.
People don't start out going for the presidency (and they shouldn't, as the obvious recent mistake of a president shows).
Slowing down fascism provides opportunity for progressive politicians to make moves in the right direction, and take positions that are higher up the ladder.
Allowing a nose dive to fascism prevents the progressive folks from having an opportunity.
In short - yes, slowing it down is good enough at the presidential level.